Week 26 · Second trimester
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Week 26 fetal development and pregnancy guide — length about 35.6cm, weight 约760g (about the size of a a leek)

Your baby is now about 35.6cm and 约760g, about the size of a a leek.

Medical references: WHO INTERGROWTH-21st · China Prenatal & Pregnancy Care Guide · ACOG

View each day of week 26 →

Week 26 fetal development milestones: length / weight / ultrasound data

Key developmental changes during week 26:

  • The retinas develop rapidly, and the eyelids begin to open and sense changes in brightness through the abdominal wall.
  • Surfactant production rises greatly and the lungs mature rapidly.
  • Brain neural connections build faster, and brain-wave activity can already be detected (showing wake-like and sleep-like patterns).
  • The volume of swallowed amniotic fluid increases to help the digestive system mature, and the baby starts rhythmic "hiccups".
  • The hearing system matures — response to the parents’ speech and music is more obvious, the baby startles at loud noises and facial expressions change with music.
  • The nails reach the fingertips and the hand and foot movements are flexible and strong.
  • In a male baby, the testicles begin descending from the abdominal cavity into the scrotum (taking about 2-3 months, mostly reaching the scrotum before birth).
  • Subcutaneous fat starts to accumulate and the skin wrinkles gradually reduce.
  • The sleep-wake cycle is regular and fetal movement has obvious active periods.
  • About 35.6cm long, about as long as a leek, weighing about 760g.
Illustration of your baby about the size of a leek at week 26 (about 35.6cm/约760g)
Week 26 size: about the size of a a leek
BPD (biparietal diameter)64.7mmWidth across the head; reflects brain development
AC (abdominal circumference)215.4mmAbdomen circumference; reflects nutrient absorption
FL (femur length)46.6mmThigh bone length; tracks gestational age
Ultrasound parameters at week 26: BPD 64.7 mm, AC 215.4 mm, FL 46.6 mm (median reference)
Week 26 three core ultrasound parameters (median; varies by individual)

* Values are medians from WHO/China standards; individual variation is normal. References: WHO INTERGROWTH-21st, China Prenatal & Pregnancy Care Guide, ACOG guidelines.

Week 26 daily development

Your baby quietly grows every day of week 26. Tap any day to see fetal development, maternal changes, and daily guidance for that day.

176Day 1Your baby opens its eyes for the first time today and can sense changes in brightness through the abdominal wall! The eyelids (previously closed) start to open this week and the retinas are developing rapidly. When you stand by a window with sunlight falling on your belly, the baby feels a warm, vague world of light. But don’t deliberately shine a torch on your belly for "light fetal education" — light through the belly is faint and a deliberately bright light may disturb the baby’s rest. The best "visual fetal education" is your daily, regular exposure to natural light.177Day 2Your baby’s hearing matures further — it responds more calmly to familiar sounds (mum’s heartbeat, speech rhythm, music you often hear) and may startle at sudden loud noises. Today pick a piece of gentle music you like (volume no higher than 60 decibels), gently stroke your belly and listen quietly for 10-15 minutes. This mainly helps you relax, and in the calm atmosphere the baby also rests more peacefully.178Day 3Eat "tomato tofu fish soup" today: soft tofu for calcium, fresh fish fillets (choose sea bass or cod) for DHA and quality protein, and the vitamin C in tomato helps iron absorption — calcium, iron and DHA in one light, easy-to-digest pot. Drop the fish fillets in last and cook just until they turn colour (about 1 minute) or the flesh turns tough; don’t over-salt the soup — it’s fresh enough on its own.179Day 4From this week watch your standing and sitting posture — the clearly protruding belly shifts your centre of gravity forward, so the pelvis tilts forward and the lumbar spine over-arches without you realising. Correct standing: press the shoulders back, keep the chest out and abdomen in (don’t push the belly out boldly), knees slightly bent; correct sitting: sit fully in the chair, place a small cushion at the lower back and set both feet flat on the floor without crossing your legs. Check your posture in the mirror for a few seconds each day; building the habit relieves lower-back pain noticeably.180Day 5Start learning about the Lamaze breathing technique — it eases delivery pain by shifting attention through a particular breathing rhythm. This week just watch a few intro videos to understand the principle; no rush to practise. It’s recommended to learn it systematically from week 28 and practise daily, with dad practising alongside — he’s not a bystander, he’s your "breathing coach" in labour.181Day 6The OGTT’s last window — if you haven’t done it, booking it this week is a must (weeks 24-28). You need to fast (no eating for 8-12 hours the night before) but not hold urine; eat normally the day before, then on the day draw blood fasting, drink 75g glucose water, and draw again at 1 hour and 2 hours. Bring a book or a downloaded audiobook to pass the wait, and prepare a small piece of wholewheat bread and warm water in a thermos to refuel right after.182Day 7Review your second-trimester weight gain today: a standard-BMI woman gains about 7.5-10.5kg cumulatively by week 26, about 0.4-0.5kg a week. Open your pregnancy weight record and see whether your gain curve is a smooth ascending arc — too great or too flat a swing is worth attention. If it deviates clearly, take it to your prenatal-care doctor and adjust this quarter’s diet and exercise plan together.

Week 26 belly changes

Illustration of belly changes at week 26: uterine position and abdominal prominence

At week 26 (second trimester) the uterus rises from the pelvis into the abdomen and most mums start to "show" — a gentle bump. First-time mums usually show a little later than mums who've been pregnant before; the fundal height sits between the navel and pubic bone.

Week 26 maternal body changes and common symptoms

  • The uterine fundus is about 6cm above the navel.
  • Cumulative weight gain is about 7.5-10.5kg.
  • Lower-back pain may worsen (forward centre of gravity, ligament relaxation, increased abdominal load).
  • Fetal movements are strong and forceful — you can see the belly pushed up.
  • Heartburn, bloating and constipation may appear.
  • Swelling of the hands and feet, leg cramps and varicose veins may worsen.
  • Braxton Hicks false contractions may appear.
  • The breasts enlarge and colostrum is secreted.

Week 26 nutrition advice and recommended recipes

As the third trimester nears, do a "nutrition push" to make sure calcium, iron, DHA and quality protein are all ample: arrange milk + egg + fish/lean meat + soy products + vegetables + fruit + whole grains each day for balanced nutrition without skimping on any group. Daily targets: quality protein about 70g, calcium 1000mg, iron 27mg, DHA 200-300mg, fiber 25-30g, iodine 230μg, about 340 extra kcal (ACOG). Keep controlling sugar (especially with GDM): cut sugary drinks and mix coarse and fine grains in staples. Avoid alcohol, raw or unpasteurised milk products, high-mercury fish, caffeine ≤200mg a day.

DHA1000mgBrain & vision development
Recommended recipeTomato tofu fish soup

Tofu brings calcium, fish fillet brings DHA and quality protein, and the vitamin C in tomato helps iron absorption — a soup that is fairly complete, light and easy to digest. Choose low-mercury fish such as sole or sea bass, remove every bone, and don’t make the soup too salty.

Week 26 prenatal education guide

The core of "fetal education" is still to help the mother-to-be relax and go with the flow; there is no strong evidence that any specific stimulation makes the baby smarter. A special note: the "shine a torch on the belly" light fetal education circulating online has limited evidence and isn’t recommended — your baby’s eyelids are just starting to open and light through the abdominal wall is faint, so deliberate light has no proven benefit and a bright light may disturb the baby’s rest. This week the baby’s hearing is mature and response to sound is obvious: talk gently or read a picture book 5-10 minutes at a set time daily, combined with gentle belly stroking; choose soothing music or white noise at a volume ≤60 decibels for 15-20 minutes a day to relax yourself. Treating fetal education as a ritual of caring for mum’s mood is the most practical.

Week 26 partner's role

①Learn delivery knowledge with your partner: understand the three stages of labour, the Lamaze breathing technique and the hospital-bag contents (systematically practising breathing after week 28 is recommended). ②Help her relieve lower-back pain: remind her of correct standing and sitting posture, prepare a pregnancy pillow and warm compress, gently massage the back (avoiding the belly). ③Lean close to the belly each day at a set time to talk or read a picture book — the baby’s hearing is mature and responds more to dad’s voice. ④Keep preparing high-nutrition meals and walking with her for sugar control.

Week 26 checkup reminders

Complete the OGTT within weeks 24-28 (arrange it soon if not yet done). Regular prenatal visit this week: weight, blood pressure, fundal height, abdominal circumference, fetal-heart auscultation, and urinalysis (check urine protein and glucose). After week 28, prenatal visits change to every two weeks and you formally begin counting fetal movements. You can also learn about and book the 30-32-week small scan (anomaly-late ultrasound) to assess growth, amniotic-fluid volume, placental position and maturity, and fetal position.

Week 26 key concerns

Complete the OGTT (if not done)Nutrition push for the third trimesterRelieve lower-back painLearn delivery knowledge/Lamaze breathing30 minutes of moderate exercise daily (ACOG recommends 150 minutes a week across pregnancy)

Signs that need immediate care at week 26

If any of the following occurs, contact your obstetrician or seek care promptly: ① persistent vaginal bleeding or brown discharge; ② sudden leakage of fluid from the vagina (possible premature rupture of membranes); ③ regular contractions (once every 10 minutes or more often) with lumbar heaviness/downward pressure (watch for preterm labour); ④ a fever over 38℃ that does not come down; ⑤ severe lower-back/waist pain with fever, chills or abnormal urination (watch for pyelonephritis); ⑥ severe headache, blurred vision or severe upper-abdominal pain (watch for preeclampsia — check blood pressure and urine protein); ⑦ itching all over, especially palms and soles with no rash (watch for ICP); ⑧ clearly reduced fetal movement or swelling, warmth and pain in one leg (watch for a clot).

Week 26 frequently asked questions

What is the Lamaze breathing technique and when do I learn it?
Lamaze reduces delivery pain by combining a particular breathing rhythm with relaxation and distraction. It’s recommended to study it systematically after week 28 and practise daily until it becomes muscle memory; practising with dad works better and comes in handier during labour.
How do I relieve lower-back pain at week 26?
A forward centre of gravity, relaxin loosening the ligaments and increased abdominal load are the main causes. Avoid long standing or sitting, wear supportive low-heeled shoes, stand with the chest out and abdomen in without arching back, side-sleep with a pregnancy pillow between the legs, do prenatal yoga and pelvic-floor exercise, and apply local warmth. Sharp pain on one side or with bleeding and fever needs care.
Can my baby see light yet — should I do "light fetal education"?
This week your baby’s eyelids are just beginning to open and can sense brightness and darkness through the abdominal wall, but shining a torch on the belly for "light fetal education" isn’t recommended — light through the belly is faint, there’s no proven benefit, and a bright light may disturb the baby’s rest. Talking, reading picture books and listening to soothing music are steadier choices for fetal education.
Is it too late to do the OGTT at week 26?
No. The OGTT window is weeks 24-28, so at week 26 book it as soon as possible and don’t let it pass week 28. Eat normally for the 3 days before, fast for 8-12 hours the night before, and arrive at the hospital fasting.
How do I read the week-26 ultrasound report?
The three measurements at 26 weeks: BPD (biparietal diameter) about 64.7mm, AC (abdominal circumference) about 215.4mm, and FL (femur length) about 46.6mm, reflecting head, abdomen and leg development. If the three are in step, growth is good; a single slight deviation isn’t necessarily abnormal — go by your obstetrician’s overall assessment.
How much weight gain is normal at week 26?
For a standard BMI, about 0.4-0.5kg a week in the second trimester, with a cumulative gain of roughly 7.5-10.5kg by week 26 being common. Watch the overall trend — use a weight-gain calculator to manage by BMI — and discuss with the doctor if it’s too fast or too slow.
What is the anomaly-late scan (small scan) and when is it done?
The small scan (30-32-week ultrasound) differs from the big anomaly scan: the big scan focuses on screening structural malformations, while the small scan focuses on assessing fetal growth, amniotic-fluid volume, placental position and maturity, fetal position, and umbilical blood flow. They serve different purposes and both are needed — you can book this one ahead from this week.
What about constipation and haemorrhoids at week 26?
Eat more coarse grains and vegetables for dietary fiber, drink 1.5-2L of water daily, walk after meals, toilet regularly without squatting long; soak in warm water for haemorrhoids. In serious cases consult a doctor about pregnancy-safe medication rather than using a stimulant laxative yourself; discuss with your doctor if iron worsens constipation.
Is there a recommended exercise duration in pregnancy?
ACOG advises women without complications about 150 minutes of moderate-intensity exercise accumulated weekly (walking, prenatal yoga, swimming), split over 5 days at about 30 minutes a day. Avoid intense exercise and pressure on the abdomen; stop and seek care for pain or bleeding.
Should I get the flu vaccine in pregnancy?
It’s recommended. The CDC and ACOG recommend that pregnant women receive the inactivated flu vaccine: pregnant women are at higher risk of severe flu, the vaccine protects mother and baby, and it is safe at every stage. During flu season (September to April) you can get vaccinated; tell them you’re pregnant.
Can I have sex at week 26?
If there’s no placenta praevia, bleeding, cervical insufficiency or threatened preterm labour, gentle sex is fine using positions that don’t press on the belly and with gentle movements. Pause if you feel unwell or the doctor advises against it; see a doctor for post-sex bleeding or pain.
What if I sleep poorly at week 26?
A growing belly, frequent urination and trouble turning over affect sleep. Use a pregnancy pillow for support, sleep on your left side, soak your feet before bed to relax, reduce evening fluids to cut night urination, and exercise moderately during the day. Avoid screens before bed and caffeinated drinks.
What about leg cramps at week 26?
When a cramp hits, flex the foot and massage the calf. Prevention: supplement calcium and magnesium, drink water, stretch before bed, wear support stockings, and avoid long standing or sitting. If cramps are frequent with weakness and numbness, check blood calcium, magnesium and electrolytes at a prenatal visit.
What should I avoid eating at week 26?
Avoid raw or undercooked meat, fish and eggs, high-mercury large fish, unpasteurised dairy, alcohol, caffeine over 200mg a day, and excess animal liver. If you have GDM, strictly control refined sugar and sugary drinks as well.
Are the fetal movements regular at week 26?
This week movements are strong and forceful with obvious active periods (after meals, at night), and you can see the belly pushed up. Keep getting familiar with your baby’s routine in preparation for formally counting movements after week 28; seek care promptly if movement clearly decreases.
What about heartburn and bloating at week 26?
Eat smaller meals more often and chew slowly, sit or stand for 30 minutes after meals before lying down, avoid eating in the 2-3 hours before bed, avoid spicy, greasy, overly sweet food and carbonated drinks, and prop up your upper body when sleeping. In serious cases, use a pregnancy-safe antacid under a doctor’s guidance.
Is more discharge at week 26 normal?
Higher oestrogen increases white discharge; milky-white or clear and odourless is normal. Watch for turning yellow-green, foul-smelling, with itching (infection), or a sudden large amount of watery leakage (rupture of membranes) — seek care the moment these appear. Wear cotton underwear and don’t douche.
What about swelling at week 26?
Mild swelling after long standing or sitting is common; raise your legs, lie on your left side, walk to promote return flow, and moderately limit salt. If the swelling suddenly worsens, spreads to the face and hands, or comes with headache or vision changes, check your blood pressure to rule out preeclampsia.
⚡The gestational-development data on this tool is compiled from the WHO INTERGROWTH-21st fetal growth standards, ACOG (American College of Obstetricians and Gynecologists), and the Chinese Medical Association's Guidelines for Pre-conception and Prenatal Care, and is reviewed for consistency by obstetrics consultants against those authoritative standards. Daily developmental tips, maternal changes, and nutrition advice follow an evidence-based approach. Note that fetal length is measured differently by week: crown–rump length (CRL) at or before week 20, and crown–heel length (CHL) from week 21 — values either side of week 21 are not directly comparable, which is a normal measurement change.

Data sources & notes

This tool provides algorithm-based estimates from the authoritative standards above for pregnancy time planning and general reference. It does not replace a doctor's diagnosis or individualized medical advice; follow your obstetrician for all prenatal care decisions.

Week 26 daily focus

Key daily tips for this week; tap any item to view the full development and guidance for that day.

Day 1Your baby opens its eyes for the first time today and can sense changes in brightness through the abdominal wall! The eyelids (previously closed) start to open this week and the retinas are developing rapidly. When you stand by a window with sunlight falling on your belly, the baby feels a warm, vague world of light. But don’t deliberately shine a torch on your belly for "light fetal education" — light through the belly is faint and a deliberately bright light may disturb the baby’s rest. The best "visual fetal education" is your daily, regular exposure to natural light.Day 2Your baby’s hearing matures further — it responds more calmly to familiar sounds (mum’s heartbeat, speech rhythm, music you often hear) and may startle at sudden loud noises. Today pick a piece of gentle music you like (volume no higher than 60 decibels), gently stroke your belly and listen quietly for 10-15 minutes. This mainly helps you relax, and in the calm atmosphere the baby also rests more peacefully.Day 3Eat "tomato tofu fish soup" today: soft tofu for calcium, fresh fish fillets (choose sea bass or cod) for DHA and quality protein, and the vitamin C in tomato helps iron absorption — calcium, iron and DHA in one light, easy-to-digest pot. Drop the fish fillets in last and cook just until they turn colour (about 1 minute) or the flesh turns tough; don’t over-salt the soup — it’s fresh enough on its own.Day 4From this week watch your standing and sitting posture — the clearly protruding belly shifts your centre of gravity forward, so the pelvis tilts forward and the lumbar spine over-arches without you realising. Correct standing: press the shoulders back, keep the chest out and abdomen in (don’t push the belly out boldly), knees slightly bent; correct sitting: sit fully in the chair, place a small cushion at the lower back and set both feet flat on the floor without crossing your legs. Check your posture in the mirror for a few seconds each day; building the habit relieves lower-back pain noticeably.Day 5Start learning about the Lamaze breathing technique — it eases delivery pain by shifting attention through a particular breathing rhythm. This week just watch a few intro videos to understand the principle; no rush to practise. It’s recommended to learn it systematically from week 28 and practise daily, with dad practising alongside — he’s not a bystander, he’s your "breathing coach" in labour.Day 6The OGTT’s last window — if you haven’t done it, booking it this week is a must (weeks 24-28). You need to fast (no eating for 8-12 hours the night before) but not hold urine; eat normally the day before, then on the day draw blood fasting, drink 75g glucose water, and draw again at 1 hour and 2 hours. Bring a book or a downloaded audiobook to pass the wait, and prepare a small piece of wholewheat bread and warm water in a thermos to refuel right after.Day 7Review your second-trimester weight gain today: a standard-BMI woman gains about 7.5-10.5kg cumulatively by week 26, about 0.4-0.5kg a week. Open your pregnancy weight record and see whether your gain curve is a smooth ascending arc — too great or too flat a swing is worth attention. If it deviates clearly, take it to your prenatal-care doctor and adjust this quarter’s diet and exercise plan together.

Content sources & notes

This guide references WHO INTERGROWTH-21st standards, the China Prenatal & Pregnancy Care Guide, ACOG clinical guidelines and BabyCenter (medically reviewed).

This page is educational pregnancy information for general reference and does not replace the diagnosis or advice of a licensed healthcare provider.

View the full fetal BPD/AC/FL reference table (weeks 14–42) →

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